Described herein is a method for operating a display device of a motor vehicle, wherein the display device is designed to output a digital image on a display surface of the motor vehicle. A display device is in this case an apparatus or an apparatus component that is configured to display image content. The display device may output a digital image on a display surface of the motor vehicle, that is to say on that surface on which the digital image appears to a user. It is possible to use augmented reality by way of the method described herein.
For a user of a motor vehicle, there are computer programs that use augmented reality and, to execute these programs, the user puts on data glasses. Such programs are intended to be used, for example, in what are called driverless motor vehicles, that is to say in motor vehicles that drive autonomously. To this end, there may be provision for the data glasses to capture a viewing direction of the user and to enable exact positioning of a virtual image on a defined display region, that is to say on a defined subregion of the display field of the display device. The display device is in this case configured as a spectacle lens of the data glasses. A camera image of a real depiction may thus be overlaid with an augmented reality, for example.
Such data glasses are positioned directly in front of the eyes of the user, as a result of which the user, even when moving his head, always looks at the display surface in a front-on view, and a digital image to be displayed is perceived in undistorted form. In the case of using computers with a screen instead of data glasses, the screen is turned such that the viewer faces the screen front-on.
If neither data glasses nor a computer are used, in the case for example of using a head-up display with a windshield, the problem arises that the driver or the occupants use a relatively large display surface that is further away from them under some circumstances.
Above all, if the user wishes for example to use a side window pane of a driverless vehicle as display surface, a text displayed by way of augmented reality may be strongly distorted and difficult to read under some circumstances, as the user looks obliquely through the window pane in some circumstances as he is strapped in during the journey. Application programs (“apps”) for augmented reality are able to be used in connection with a windshield or a side window pane, but the depiction of the augmented reality is often perceived in distorted form. For a depiction without distortion, a computer screen has to be fastened for example to the windshield or held in front of it in order to use this application program.
The problem arising from the related art is illustrated in FIGS. 1a and 1b. FIGS. 1a and 1b each show a display surface 10 with a digital image 12 displayed thereon. In FIG. 1a, the situation is illustrated from the view of a user who is standing or sitting in front of the display surface 10 and is seeing the digital image 12 in undistorted form. FIG. 1b shows the situation in which the user is standing or sitting to the side of the display surface 10 and thus perceives not just the display surface 10 but also the digital image 12 in perspectively distorted form. The relative form, brought about by perspective, of the digital image 12 of FIG. 1b has the effect that the user perceives the digital image 12 as a tapering object that is arranged closer to a more remote edge of the display surface 10 than to an edge of the display surface 10 being faced. If the digital image 12 shows writing or a text, for example, this is not easily able to be read.
German Patent Application Publication DE 10 2013 215 370 A1 proposes incorporating information about a driving situation or driving intentions, for example of a vehicle in front, onto the windscreen using a head-up display. A similar method is proposed by German Patent Application Publication DE 10 2014 207 398 A1, in which a camera external to the motor vehicle records the surroundings. A corresponding device for a rear camera is described in German Patent Application Publication DE 199 11 648 A1.
German Patent Application Publication DE 10 2006 050 547 A1 proposes a variant in which a virtual image is projected onto a virtual image plane outside the motor vehicle.
The disadvantage furthermore exists, however, that large users perceive a depicted image in distorted form, for example. To this end, German Patent Application Publication DE 10 2012 201 805 A1 proposes, in the case of a stereoscopic display apparatus, to correct what is called crosstalk of interfering data in an item of image content. German Patent Application Publication DE 10 2013 212 667 A1 discloses a method in which preliminary distortion of an image for a first eye of the viewer takes place, as well as preliminary distortion of a second image for a second eye of the viewer. A three-dimensional image is generated therefrom.
The related art furthermore has the disadvantage, however, that the methods mentioned above are performed by the manufacturer and do not take into account individual requirements of a passenger. Augmented reality is therefore only able to be provided to a limited extent.